The present invention relates generally to a master cylinder, and in particular to a master cylinder having a pair of interface members sandwiched between two housing parts connected together.
The invention concerns a type of master cylinder known generally as a recessed cartridge master cylinder and disclosed in U.S. Pat. No. 4,718,234. The master cylinder includes two die cast components one of which is threaded into the other. The assembly of the two die cast components is sensitive to assembly torque. The assembly torque directly affects the master cylinder function due to the compression set of the plastic components which could possibly close off the pumping flow ports even though they were open during production testing. The male/female threads of the two die cast components have very tight tolerances which are required in order to orient the internal components with respect to concentricity. During assembly, several individual seal components must be oriented during assembly. The assembly and function of the seals is sensitive to diametric fit, roundness, and concentricity of several components. The outlet ports extend to the side and this dictates the location and orientation of a fluid level indicator within the reservoir in addition to the shape of the reservoir in order to permit access for tools which receive the brake line tube nuts. The reservoir is typically held to the housing by means of a wire retainer. Because of the shape of the die cast housing, the die utilized results in a limited number of cavities. These can be difficult to maintain since the diameters are large. It is highly desirable to eliminate or mitigate a large number of the above problems while still providing a very short recessed cartridge type of master cylinder which provides a significant reduction in packaging space under the hood of an automotive vehicle. Such packaging space has become important with the advent of adaptive braking control systems which can require considerable space within the vehicle motor area.